package com.yaj.myfactorysupport.config.security;

import cn.hutool.core.date.DateUtil;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class JwtTokenUtil {
    public static final String CLAIM_KEY_USERNAME="sub";
    public static final String CLAIM_KEY_CREATED="created";

    @Value("${jwt.secret}")
    private String secret;

    @Value("${jwt.expiration}")
    private Long expiration;

    /**
     * 根据用户信息生成token
     * @param userDetails
     * @return
     */
    public String generateToken(UserDetails userDetails){
        Map<String ,Object> claims = new HashMap<>();
        claims.put(CLAIM_KEY_USERNAME,userDetails.getUsername());
        claims.put(CLAIM_KEY_CREATED, DateUtil.date());

        return generateToken(claims);
    }

    /**
     * 从token中获取登录用户名
     * @param token
     * @return
     */
    public String getUserNameFromToken(String token){
        String username;
        try {
            Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        } catch (Exception e) {
            username = null;
        }
        return username;
    }

    /**
     * 判断token是否有效
     * @param token
     * @param userDetails
     * @return
     */
    public boolean validateToken(String token,UserDetails userDetails){
        String username = getUserNameFromToken(token);
        return username.equals(userDetails.getUsername()) && !isTokenExpired(token);
    }

    /**
     * 判断token是否可以被刷新
     * @param token
     * @return
     */
    public boolean canRefresh(String token){
        return !isTokenExpired(token);
    }

    /**
     * 刷新token
     * @param token
     * @return
     */
    public String refreshToken(String token) {
        Claims claims = getClaimsFromToken(token);
        claims.put(CLAIM_KEY_CREATED, DateUtil.date());

        return generateToken(claims);
    }

    /**
     * 判断token是否失效
     * @param token
     * @return
     */
    private boolean isTokenExpired(String token) {
        Date expireDate = getExpriedDateFormToken(token);
        return expireDate.before(DateUtil.date());
    }

    /**
     * 从token中获取失效时间
     * @param token
     * @return
     */
    private Date getExpriedDateFormToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return  claims.getExpiration();
    }

    /**
     * 从token中获取荷载
     * @param token
     * @return
     */
    private Claims getClaimsFromToken(String token) {
        Claims claims = null;
        try {
            claims = Jwts.parser()
                        .setSigningKey(secret)
                        .parseClaimsJws(token)
                        .getBody();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return claims;
    }

    /**
     * 根据荷载生成JWT TOKEN
     * @param claims
     * @return
     */
    private String generateToken(Map<String,Object> claims){
        return Jwts.builder()
                .setClaims(claims)
                .setExpiration(gengerateExpriationDate())
                .signWith(SignatureAlgorithm.HS512,secret)
                .compact();
    }

    /**
     * 生成token失效时间
     * @return
     */
    private Date gengerateExpriationDate() {
        return new Date(System.currentTimeMillis() + expiration*1000);
    }
}
